CN109490241A - Quick dynamic Terahertz near field imaging system and its construction method based on photoconductive antenna array - Google Patents
Quick dynamic Terahertz near field imaging system and its construction method based on photoconductive antenna array Download PDFInfo
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Abstract
The invention discloses quick dynamic Terahertz near field imaging systems and its construction method based on photoconductive antenna array, the described method comprises the following steps: the micro Process of the design of probe unit structure, photoconductive antenna array that prepare optimization manufactures, realization carries out gate excitation to detection array using spatial light modulator and builds pulsed terahertz imaging system.Compared with prior art, the invention has the following advantages that (1) quick dynamic Terahertz near field imaging system of the present invention based on photoconductive antenna array realizes the photoconductive antenna array that THz wave efficiently detects, resolution ratio is better than λ/10, and unit signal-to-noise ratio is better than 70dB；(2) system carries out gate excitation to photoconductive antenna array using spatial light modulator, and combines multichannel phase lock amplifying technology, realizes a kind of dynamic, flexible, efficient, quick collecting method.
Description
Technical field
The invention belongs to THz imaging technologies, are related to a kind of terahertz imaging system, are specially based on photoconductive antenna
The quick dynamic Terahertz near field imaging system and its construction method of array.
Background technique
THz imaging technology is grown up on the basis of time-domain spectroscopy system.Typical terahertz imaging
Sample is usually placed in Terahertz system by system, by utilizing two-dimensional scanning platform mobile example or single point detector,
To note down the transmission or reflection information of sample different location.Terahertz time-domain waveform is extracted to each pixel of sample,
Sample image is rebuild by data processing.Since Hu et al. is for the first time using transmission-type Terahertz point by point scanning imaging technique to chip
Since internal structure and leaf water content are imaged, THz imaging technology causes the extensive concern of people and obtains
It rapidly develops.Since this method can be by phase lock amplifying technology noise reduction, high s/n ratio imaging may be implemented, and (signal-to-noise ratio reaches
To 104Or higher).However, since traditional Terahertz single-point imaging system generallys use the measurement method of point-by-point mechanical scanning,
Sweep time is long, and acquisition speed is slow.Imaging time depends on sample size and scanning step.Our research works in early period
It finds in work, when one target having a size of 8mm × 8mm is imaged using the single point detector based on the method, needs
Time-consuming 10h or more (scanning step: 250 μm).Therefore, this method is unfavorable for carrying out object to be measured dynamic measurement or in real time prison
Control.In addition, during the scanning process, the power swing or sample to be tested physical state or chemistry of laser source and THz source are special
The variation of property, can all influence imaging results, this undoubtedly limits the imaging mode in the application in the fields such as industry monitoring.
Imaging technique based on compression sensing (Compressive sensing) can significantly improve the figure of single point detector
As acquiring speed, and signal-to-noise ratio with higher.Using the theory, can by algorithm by a sparse picture signal from
It is rebuild in the measurement result of height lack sampling.Therefore, it can be rebuild from a small amount of measured value much smaller than the total pixel of image
Original image, significantly shortening imaging time.Single pixel camera based on the theory most early in visible light wave range propose, and then in
It is expanded by Chan to terahertz wave band within 2008.The system generally carries out sparse adopt to target image using multiple random mask plates
Sample, and sampled value is measured using single point detector, target image is rebuild using algorithm later.Initially, the sparse sampling of sample by
Several groups metal mask plate before being applied to sample is realized, but requires manual switching mask plate due to measuring every time, time-consuming to take
Power.In recent years, this method receives very big concern, researcher propose it is a variety of can switching at runtime mask plate realization side
Formula, such as the spatial light modulator based on Meta Materials and the light-operated Terahertz amplitude modulator of silicon substrate, have greatly pushed the field
Further development.
Another mode that can significantly improve terahertz imaging speed is using array Detection Techniques.It is relatively common
Be the sampling technique based on electrooptic effect and the Detection Techniques based on photoconductive antenna.Wherein, electro optic sampling technology is using electricity
Luminescent crystal (such as ZnTe) and area array CCD camera are as detection device.This method is not necessarily to carry out two-dimensional scanning energy directly to sample
The shortcomings that extracting entire sample two-dimensional signal, therefore single point detector point by point scanning can be overcome to take long time, significantly improves
Image taking speed, and sample can be monitored in real time.However, in practical applications, since system passes through CCD to Terahertz figure
As information is acquired, lock-in amplifier noise reduction can not be utilized, therefore the signal-to-noise ratio of system is received and greatly limited, this is also hindered
Its further industrial development is hindered.
The imaging technique of array based on photoconductive antenna can use phase lock amplifying technology and obtain high s/n ratio, while can
To realize fast imaging.It is typically achieved in that and multiple photoconductive antenna units is integrated in same semiconductor core on piece, lead to
Cross by femto-second laser pulse focus to antenna element gap it is carried out high speed gate excitation (Optical gating), Ke Yishi
Existing Sample Scan imaging.Herrmann et al. succeeded in developing 8 channel terahertz imaging arrays in 2002 for the first time.In the system
In, in order to realize the gate excitation to array element, the femtosecond laser source after expanding is focused to entire aerial array area by author
Domain, only about 5% laser energy are efficiently used by array element gap, and extra laser energy causes high background and makes an uproar
Sound, therefore limit it and further develop.Then, Pradarutti et al. proposes to carry out femtosecond laser using microlens array
Then beam splitting and the electrode gap for focusing to each antenna element respectively are come using multichannel phase lock-in detecting technology while reading 16
The data in a channel.System signal-to-noise ratio with higher (suitable with individual antenna).However, since microlens array prepares work
Skill is complicated, and with aerial array alignment difficulties, spatial resolution is restricted to~500 μm.
Further, since THz wave wavelength is longer, limited by diffraction effect, point of traditional far field terahertz imaging system
Resolution is its wavelength magnitude, constrains the application of THz imaging technology to a certain extent.Therefore, develop near field detection imaging
Technology is particularly important for obtaining higher imaging resolution.Report relatively common at present has based on probe-type, aperture
The Near-Field Radar Imaging means of method and high order focusing light beam.
The processing of photoconductive antenna array is one of key technology of terahertz imaging.Terahertz photoconductive antenna most earlier than
It is proposed by Auston and Grischkowsky et al. the eighties in last century, and goes so far as now, having become one kind at present
Commonplace terahertz sources, detection means.THz wave transmitting and detection based on this means are required to swash by femtosecond
It rises to realize.For different femtosecond excitation source categories and its operation wavelength (such as 800nm, 1550nm and 1030nm), lining
Bottom material and micro fabrication are different.Under normal circumstances, photoconductive antenna may act as terahertz transmitter, while
It can be used as receiver.But the working efficiency to be optimal, different operating modes to the selection of antenna material characteristic and
Processing technology has different requirements.For example, terahertz transmitter generally requires base material with high electron mobility, and terahertz
Hereby receiver generally requires extremely short carrier lifetime and high resistivity.Current terahertz time-domain system generallys use near-infrared
Titanium sapphire laser device as laser source.For the operation wavelength (800nm), relatively common base material has radiation injury
Silicon on sapphire or low-temperature epitaxy GaAs.Compared with silicon on sapphire, the GaAs material of low-temperature epitaxy has shorter load
It flows the sub- service life, broader frequency and higher signal strength, therefore, is more advantageous to and carries out THz wave detection.To being at present
Only, researcher has conducted extensive research the photoconductive antenna of different structure, such as dipole-type (Dipole), bow-tie type
(Bowtie), screw type (Spiral antenna) etc..However, due to lacking a kind of flexible, efficient, quick array gate
Mode of excitation, the most structure designs for being confined to single-point type antenna element of current research report (and photoconductive antenna of business)
And performance study.
Summary of the invention
The technical issues of solution: it for overcome the deficiencies in the prior art, obtains a kind of with high-resolution, high s/n ratio
Photoconductive exploring antenna array, and explore its array dynamic optical gate excitation technique based on spatial light modulator；Pass through
Using multichannel lock-in amplifier parallel acquisition data, high s/n ratio, quick Terahertz Near-Field Radar Imaging are realized, the present invention provides
Quick dynamic Terahertz near field imaging system and its construction method based on photoconductive antenna array.
Technical solution: the construction method of the quick dynamic Terahertz near field imaging system based on photoconductive antenna array, institute
State method the following steps are included:
Step 1, the probe unit structure design of preparation optimization
Research and analyse photoconductive antenna substrate material properties, different antennae structure and size and excitation laser pulse characteristic
Influence to terahertz detection performance, and is carried out by numerical simulation and is tested for it using Finite-Difference Time-Domain Method and electromagnetic simulation software
Card；
The micro Process manufacture of step 2, photoconductive antenna array
According to excitation optical source wavelength and the operating mode of antenna element, selects antenna material or determine its production technology, obtain
There must be the semiconductor material of short carrier lifetime and high resistivity characteristic；In addition, selection antenna electrode material or its determining life
Production. art forms good Ohmic contact with base material；Finally, utilizing photoetching, the method patterned metal electrode of etching；
Step 3, realization carry out gate excitation to detection array using spatial light modulator
According to system requirements, selective transmission formula or reflection type liquid crystal spatial light modulator, and research and utilization its carry out photoelectricity
Lead antenna array efficiently gates the feasibility of excitation: expanding first to femtosecond pulse, then utilizes space light modulation
Device is split incident beam, modulates, and finally focuses to probe unit gap respectively；Under the influence of control signals, right
Detection array carries out simultaneously, partially or successively sequentially gate excitation；The number of research and utilization low noise amplifier and lock-in amplifier
According to acquisition technique, it is ready for subsequent realization terahertz imaging；
Step 4 builds pulsed terahertz imaging system
Use titanium sapphire mode locking femto-second laser for excitaton source, and be classified as pumping pulse and detection using beam splitter
Pulse, the former is incident on terahertz emission generation device after time delay system and generates terahertz pulse, the pulse by
Sample to be tested is focused to after a pair of of parabolic mirror, the latter divides it after optical beam-expanding, by spatial light modulator
Beam, modulation simultaneously focus to photoconductive antenna cell gap respectively, so that Terahertz antenna array unit be driven to measure；Benefit
Data acquisition is realized with low noise preamplifier and multichannel lock-in amplifier, and pumping is adjusted by control time delay system
Time delay between pulse and direct impulse detects the entire time domain waveform of terahertz pulse, by data processing, rebuild to
Sample terahertz image.
Preferably, antenna described in step 1 is dipole antenna, and structure is I shape or H-shaped.
Preferably, in step 2 antenna material select low-temperature epitaxy GaAs；Base material selects semi-insulated arsenic
Gallium, for the gallium arsenide film layer of 1 μ m-thick of 200-300 DEG C of growth.
Preferably, the spacing range between detection array and sample is 500um-3mm.
The quick dynamic Terahertz near field imaging system based on photoconductive antenna array that the building of any of the above method obtains.
The utility model has the advantages that (1) quick dynamic Terahertz near field imaging system of the present invention based on photoconductive antenna array
Realize the photoconductive antenna array that THz wave efficiently detects, resolution ratio is better than λ/10, and unit signal-to-noise ratio is better than 70dB；(2) institute
It states system and gate excitation is carried out to photoconductive antenna array using spatial light modulator, and combine multichannel phase lock amplifying technology,
Realize a kind of dynamic, flexible, efficient, quick collecting method；(3) system can be further realized based on Sparse Array
The quick terahertz imaging of column and compressive sensing theory.It, can be by algorithm by a sparse picture signal using the theory
It is rebuild from the measurement result of height lack sampling, it can rebuild original from a small amount of measured value much smaller than the total pixel of image
Beginning image, significantly shortening imaging time.The system passes through simultaneous shot and acquires in photoconductive antenna array specific position too
Hertz imaging unit, then rebuilds target image using algorithm, to realize high speed terahertz imaging.
Detailed description of the invention
Fig. 1 is the quick dynamic Terahertz near field imaging system construction method of the present invention based on photoconductive antenna array
Technology Roadmap；
Fig. 2 is photoconductive antenna unit design drawing, and (a) is H-shaped dipole antenna, is (b) I shape dipole antenna, (c) is
Simplified antenna element processing technology schematic diagram；Wherein, L is dipole length, g is gap, w is electrode width (L=80um, g
=5um, w=20um), D is electrode width, and l is that gap p is electrode pad size；
Fig. 3 is the photoconductive antenna array gate schematic diagram based on transmissive spatial optical modulator；
Fig. 4 is Terahertz near field imaging system schematic diagram.
Specific embodiment
Following embodiment further illustrates the contents of the present invention, but should not be construed as limiting the invention.Without departing substantially from
In the case where spirit of that invention and essence, to modification made by the method for the present invention, step or condition and replaces, belong to the present invention
Range.Unless otherwise specified, the conventional means that technological means used in embodiment is well known to those skilled in the art.
Embodiment 1
As shown in Figure 1, the construction method packet of the quick dynamic Terahertz near field imaging system based on photoconductive antenna array
Include following steps:
The design of step 1, photoconductive antenna array
The detection performance (efficiency, bandwidth, resolution ratio, signal strength) of photoconductive antenna depend primarily on the following because
Element: substrate material properties (such as carrier lifetime, dark resistivity, carrier mobility), antenna structure and size, and gate
Laser characteristics (such as intensity, pulsewidth, focal position, spot size).Therefore, the selection of base material and its technique, day knot
Structure, the design of size and the selection of operating mode are most important to the efficient terahertz detection of realization.
For the ease of realizing the array of photoconductive antenna and integrated, two different dipole antenna knots are mainly studied
Structure, i.e. I shape and H-shaped, in Fig. 2 shown in (a) and (b).By studying its structure snd size (such as dipole length L, gap g, electricity
Pole width w etc.) influence to Terahertz antenna detective bandwidth, efficiency and signal strength, realize the optimization design of electrode structure.
The work mainly utilizes the Comsol for being based on Finite-Difference Time-Domain Method (Finite-difference time-domain, FDTD)
Simulation softward and based on time-domain finite integration method electromagnetic simulation software (Computer simulation technology,
CST it) completes.
The micro Process preparation of step 2, photoconductive antenna array
After completing The Optimal Design of Antenna Structure, photoconductive antenna array is prepared using micro-processing technology.Antenna material choosing
With the GaAs of low-temperature epitaxy, which has shorter carrier lifetime and high resistivity under low temperature growth conditions, is to realize
The ideal material of THz wave efficient detection.The technique is in molecular beam epitaxy (Molecular beam epitaxy, MBE) equipment
Middle realization, substrate material select semi-insulated GaAs (Semi-insulating gallium arsenide, SI-GaAs),
And the gallium arsenide film layer of about 1 μ m-thick is grown at cryogenic conditions (about 200-300 DEG C).Under cryogenic, it can grow non-
The service life (subpicosecond magnitude) of carrier can be significantly reduced to form defect in stoichiometric compound.By adjusting annealing temperature
Degree, optimizes the electrical resistivity property of GaAs material, to be conducive to the detection of THz wave.Finally metal is made in gallium arsenide surface
Electrode.In order to form good Ohmic contact, Ti/Pt/Au electrode (50/100/ is sequentially depositing using electron beam evaporation process
200nm), finally, utilizing photoetching, the method patterned electrodes structure of etching.For the ease of subsequent device test lead, Wo Men
Larger-size square pad is devised in electrode structure.The structure design of two kinds of antenna elements and its simplified processing flow
As shown in Figure 2.
Step 3, the dynamic gate excitation technique research based on spatial light modulator
In order to realize fast imaging to sample to be tested using above-mentioned photoconductive antenna array, need to explore a kind of efficient battle array
The gate excitation technique of column.The purpose is realized using German Holoeye LCD space light modulator.The modulator is a kind of dynamic
State optical device is divided into transmission-type and two kinds reflective, and the two can meet project demand.Its working principle is that passing through utilization
Applied voltage changes liquid crystal molecule and is directed toward, and controls its birefringent characteristic, to realize the modulation to incident light wave amplitude, phase.
Spatial light modulator is made of many separate units (pixel), spatially lines up two-dimensional array structure, and each unit can be only
It is vertical to receive electrical signal control.Therefore, which can be split incident excitation pulse, and carry out to its amplitude and phase
It modulates respectively, finally focuses to probe unit gap respectively, and gate the unit.It under the influence of control signals, can be to spy
Survey array carry out simultaneously, part or successively sequentially excite, to realize a kind of dynamic, flexible, efficient, quick imaging method.
In Fig. 3, by taking transmission liquid crystal spatial light modulator as an example, its operating mode is illustrated.
Step 4 builds terahertz time-domain imaging system, completes the test of Terahertz Near-Field Radar Imaging
It uses Ti:Sapphire laser mode locking femto-second laser for excitation light source, builds terahertz imaging system, as shown in Figure 4.Femtosecond
Laser pulse is divided into two-way coherent light: pumping pulse and direct impulse after beam splitter.The former passes through time delay system
After be incident on terahertz transmitter and generate terahertz pulse, then by after a pair of of paraboloidal mirror through over-focusing to sample to be tested.
To improve system signal noise ratio, the commercial high power photoconductive antenna of our uses of transmitter.Direct impulse is after expanding, by transmiting
The photoconductive antenna array element gap for not adding bias voltage is modulated and is focused to respectively in the beam splitting of formula spatial light modulator, thus
Excitation generates electronic-hole to (free carrier).At the same time, the terahertz pulse synchronously arrived at is used as and is added in antenna
Bias field on unit, and carrier moving is driven, and photoelectric current is formed in antenna element.The signal passes through low noise electricity
After stream amplifier amplification, it is phase locked amplifier acquisition.By using multichannel lock-in amplifier (Signal Recovery,
Quick, high s/n ratio terahertz imaging may be implemented in 8Channel) parallel acquisition data.In addition, passing through research gate laser beam
Intensity, facula position and size, photoproduction carrier concentration and spatial distribution in adjustable photoconduction base material, thus
Further increase and optimize the detection efficient of photoconductive array.Finally, by the way that sample is abutted photoconductive antenna array, and optimize
Cellular construction design, may be implemented Terahertz Near-Field Radar Imaging, to significantly provide its imaging resolution.Utilize three-dimensional mobile platform
The spacing between detection array and sample is adjusted, influence of the different spacing to performances such as imaging resolutions can be studied, thus excellent
Change imaging system.
Claims (5)
1. the construction method of the quick dynamic Terahertz near field imaging system based on photoconductive antenna array, which is characterized in that institute
State method the following steps are included:
Step 1, the probe unit structure design of preparation optimization
Photoconductive antenna substrate material properties, different antennae structure and size and excitation laser pulse characteristic are researched and analysed to too
The influence of hertz detection performance, and numerical simulation and verifying are carried out to it using Finite-Difference Time-Domain Method and electromagnetic simulation software；
The micro Process manufacture of step 2, photoconductive antenna array
According to excitation optical source wavelength and the operating mode of antenna element, selects antenna material or determine its production technology, had
There is the semiconductor material of short carrier lifetime and high resistivity characteristic；In addition, selection antenna electrode material or determining its produce work
Skill forms good Ohmic contact with base material；Finally, utilizing photoetching, the method patterned metal electrode of etching；
Step 3, realization carry out gate excitation to detection array using spatial light modulator
According to system requirements, selective transmission formula or reflection type liquid crystal spatial light modulator, and the photoconductive day of its progress of research and utilization
Linear array efficiently gates the feasibility of excitation: expanding first to femtosecond pulse, then utilizes spatial light modulator pair
Incident beam is split, modulates, and finally focuses to probe unit gap respectively；Under the influence of control signals, to detection
Array carries out simultaneously, partially or successively sequentially gate excitation；The data of research and utilization low noise amplifier and lock-in amplifier are adopted
Collection technology is ready for subsequent realization terahertz imaging；
Step 4 builds pulsed terahertz imaging system
It uses titanium sapphire mode locking femto-second laser for excitaton source, and is classified as pumping pulse and detection arteries and veins using beam splitter
Punching, the former is incident on terahertz emission generation device after time delay system and generates terahertz pulse, and the pulse is by one
To focusing to sample to be tested after parabolic mirror, the latter is split it after optical beam-expanding, by spatial light modulator,
It modulates and focuses to photoconductive antenna cell gap respectively, so that Terahertz antenna array unit be driven to measure；Using low
Noise preamplifier and multichannel lock-in amplifier realize data acquisition, adjust pumping pulse by control time delay system
Time delay between direct impulse detects the entire time domain waveform of terahertz pulse, by data processing, rebuilds to test sample
Product terahertz image.
2. the building of the quick dynamic Terahertz near field imaging system according to claim 1 based on photoconductive antenna array
Method, which is characterized in that antenna described in step 1 is dipole antenna, and structure is I shape or H-shaped.
3. the building of the quick dynamic Terahertz near field imaging system according to claim 1 based on photoconductive antenna array
Method, which is characterized in that antenna material selects the GaAs of low-temperature epitaxy in step 2；Base material selects semi-insulated arsenic
Gallium, for the gallium arsenide film layer of 1 μ m-thick of 200-300 DEG C of growth.
4. the building of the quick dynamic Terahertz near field imaging system according to claim 1 based on photoconductive antenna array
Method, which is characterized in that the spacing range between detection array and sample is 500um-3mm.
5. the quick dynamic Terahertz Near-Field Radar Imaging based on photoconductive antenna array that the building of claim 1-4 either method obtains
System.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110333396A (en) * | 2019-06-17 | 2019-10-15 | 广州视源电子科技股份有限公司 | Field intensity imaging system and imaging method thereof |
| CN110600857A (en) * | 2019-08-30 | 2019-12-20 | 西安理工大学 | Terahertz photoconductive antenna array and detector thereof |
| CN111077151A (en) * | 2020-01-03 | 2020-04-28 | 北京航空航天大学 | Atomic spin multi-channel detection method and device based on spatial light modulator |
| CN111505629A (en) * | 2020-05-08 | 2020-08-07 | 中国科学院国家空间科学中心 | Terahertz security inspection imaging system and method |
| CN112485229A (en) * | 2020-10-29 | 2021-03-12 | 电子科技大学 | Coherent near-field detection system based on free electron excitation and photoelectric detection |
| CN112698114A (en) * | 2020-12-10 | 2021-04-23 | 北京无线电测量研究所 | Antenna near field data acquisition method and system |
| CN113218910A (en) * | 2021-05-13 | 2021-08-06 | 重庆邮电大学 | Terahertz imaging system and method based on super-surface structure |
| CN114486804A (en) * | 2021-12-29 | 2022-05-13 | 江南大学 | Broadband terahertz wave image reconstruction system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105628642A (en) * | 2016-01-08 | 2016-06-01 | 上海理工大学 | Method for improving frequency spectrum signal-to-noise ratio of tera-hertz optical detection system |
| CN105806800A (en) * | 2014-12-30 | 2016-07-27 | 深圳先进技术研究院 | Terahertz optical fiber sensing device and pollutant detection method using the same |
| CN105870582A (en) * | 2016-05-24 | 2016-08-17 | 深圳市太赫兹系统设备有限公司 | Terahertz near field probe, photoconductive antenna and manufacture method of photoconductive antenna |
-
2018
- 2018-12-07 CN CN201811495130.1A patent/CN109490241B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105806800A (en) * | 2014-12-30 | 2016-07-27 | 深圳先进技术研究院 | Terahertz optical fiber sensing device and pollutant detection method using the same |
| CN105628642A (en) * | 2016-01-08 | 2016-06-01 | 上海理工大学 | Method for improving frequency spectrum signal-to-noise ratio of tera-hertz optical detection system |
| CN105870582A (en) * | 2016-05-24 | 2016-08-17 | 深圳市太赫兹系统设备有限公司 | Terahertz near field probe, photoconductive antenna and manufacture method of photoconductive antenna |
Non-Patent Citations (4)
| Title |
|---|
| B. PRADARUTTI ET AL: "《Terahertz line detection by a microlens array coupled photoconductive antenna array》", 《OPTICS EXPRESS》 * |
| 张振伟等: "《太赫兹成像技术的实验研究》", 《红外与毫米波学报》 * |
| 李铁元等: "《低温生长砷化镓光电导天线产生太赫兹波》", 《中国激光》 * |
| 许悦红等: "《基于光导微探针的近场/远场可扫描太赫兹光谱技术》", 《物理学报》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110333396A (en) * | 2019-06-17 | 2019-10-15 | 广州视源电子科技股份有限公司 | Field intensity imaging system and imaging method thereof |
| CN110600857A (en) * | 2019-08-30 | 2019-12-20 | 西安理工大学 | Terahertz photoconductive antenna array and detector thereof |
| CN111077151A (en) * | 2020-01-03 | 2020-04-28 | 北京航空航天大学 | Atomic spin multi-channel detection method and device based on spatial light modulator |
| CN111505629A (en) * | 2020-05-08 | 2020-08-07 | 中国科学院国家空间科学中心 | Terahertz security inspection imaging system and method |
| CN111505629B (en) * | 2020-05-08 | 2021-02-02 | 中国科学院国家空间科学中心 | Terahertz security inspection imaging system and method |
| CN112485229A (en) * | 2020-10-29 | 2021-03-12 | 电子科技大学 | Coherent near-field detection system based on free electron excitation and photoelectric detection |
| CN112485229B (en) * | 2020-10-29 | 2022-03-15 | 电子科技大学 | Coherent near-field detection system based on free electron excitation and photoelectric detection |
| CN112698114A (en) * | 2020-12-10 | 2021-04-23 | 北京无线电测量研究所 | Antenna near field data acquisition method and system |
| CN112698114B (en) * | 2020-12-10 | 2023-04-14 | 北京无线电测量研究所 | Antenna near field data acquisition method and system |
| CN113218910A (en) * | 2021-05-13 | 2021-08-06 | 重庆邮电大学 | Terahertz imaging system and method based on super-surface structure |
| CN114486804A (en) * | 2021-12-29 | 2022-05-13 | 江南大学 | Broadband terahertz wave image reconstruction system |
| CN114486804B (en) * | 2021-12-29 | 2024-04-05 | 江南大学 | Broadband terahertz wave image reconstruction system |
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